WASHINGTON — The Federal Emergency Management Agency has yet to shake its poor reputation, more than two years after its mishandling of Hurricane Katrina, a poll shows.

FEMA ranked at the bottom in a new Associated Press-Ipsos poll that measured the public's views of a dozen federal government agencies. FEMA came in last, and the Internal Revenue Service and Transportation Security Administration tied for next to last. The Postal Service was the clear favorite.

FEMA got particularly low ratings in the Midwest, where 48 percent have an unfavorable view of the agency. But it got better ratings in the South, where just 38 percent held that view. There has been an equal number of federally declared disasters in the two regions this year.

FEMA administrator R. David Paulison said the agency's approval ratings would have been a lot lower two years ago. Paulison took over FEMA after the botched response to Katrina led to the departure of his predecessor, Michael Brown. In the past two years the agency has gone through major reorganizations.

The poll results show "that we really haven't got our message out," Paulison said. "We're doing some good things." As FEMA continues to respond to disasters across the country, "people will see that it's a different organization," he said.

Paul C. Light, professor of public policy at New York University, said FEMA's low ratings two years after Katrina show how difficult it is for federal agencies to recover from "egregiously poor" performances.

Light said FEMA's response to the southern California wildfires in October was good, but the fires were not as catastrophic as Katrina. FEMA needs a positive response to a Katrina-level disaster to really bounce back in the public's eyes, he said.

"The public will be watching very closely when the next hurricane hits," Light said.